<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>

    <script>

        // es6新增的语法  模板字符串

        var a = 'hi' ;
        var b = 'helli' ;
        document.write('<h1>' + a + '</h1>') ;

        // 模板字符串  ``   ${变量}
        document.write(`<h1>${b}</h1>`) ;

    </script>
    
</body>
</html>